The present invention is directed to a soap-gelled stick composition, used as a base for incorporation of various active ingredients, including deodorant active ingredients, to form various stick products, including deodorant sticks. The active ingredient is incorporated in the base composition, and is applied, e.g., to the skin when the composition having the active ingredient incorporated therein is rubbed against the skin, as known with conventional sticks. Moreover, the present invention is directed to a deodorant soap-gelled solid stick, having a deodorant active material incorporated in the soap-based gel stick composition. In particular, the present invention relates to a soap-based gel stick composition which maintains its physical form and aesthetic qualities over extended periods of time, even under high-temperature climatic conditions (that is, a gel stick composition that is stable even under hot environmental (weather or storage) conditions).
Soap-gelled solid stick compositions, for applying active ingredient to, e.g., skin of a human, are known. Current deodorant sticks in the market place (both in the United States and outside the United States) are based on sodium stearate as the soap gelling agent, the deodorant sticks having a melting temperature not greater than 59.degree. C. When exposed to hot climatic conditions, these stick products melt and/or deform, leading to aesthetically inferior products (that is, products having poor surface characteristics, exhibiting syneresis, etc.). Of course, the problem of an inferior product in hot climatic conditions is particularly acute in hot regions of the world, such as in the Far East and Latin America.
U.S. Pat. No. 4,252,789 to Broad discloses a soap-based stick composition for applying active ingredients to the skin, the composition being water-based and consisting essentially of from about 3% to about 10% by weight of a mixture of sodium stearate and sodium palmitate in a weight-ratio range from about 1:1 to about 9:1; from about 0.1% to about 3.0% by weight of a soap-compatible germicide; from about 0.1% to about 0.5% by weight of a compound selected from the class consisting of polyethylene imine and ethoxylated polyethylene imine, the compound having an average molecular weight from about 40,000 to about 100,000; and the balance being water. This patent discloses that adding polyethylene imine or ethoxylated polyethylene imine causes the resulting stick to shrink slightly on setting up, rather than expanding, so that such a stick is more readily extruded from the cylindrical case typically used for deodorant sticks. Furthermore, the temperature stability of the resulting stick is enhanced. This patent further discloses that small amounts of the salts of myristic and oleic acid are typically present in commercially available sodium stearate and sodium palmitate; and that while sodium myristate in concentrations below 5% by weight of the total soap concentration have little effect upon the stick, sodium oleate should be avoided as much as possible and should typically not be present in concentrations in excess of about 2% by weight of the total soap concentration.
Note that U.S. Pat. No. 4,252,789 requires additional materials, including an imine compound, in order to enhance temperature stability.
U.S. Pat. No. 4,504,465 to Sampson, et al discloses cosmetic compositions in the form of solid sticks, containing, as essential components, (1) a polyhydric aliphatic alcohol containing 2 or 3 carbon atoms and from 2 to 3 hydroxyl groups, suitable polyhydric alcohols including ethylene glycol, propylene glycol, trimethylene glycol and glycerine; (2) a gel-forming agent, which is a sodium or potassium salt (soap) of fatty acids containing from about 14 to 18 carbon atoms; and (3) an ethylene oxide and/or propylene oxide condensation product having the formula: EQU R(OC.sub.3 H.sub.6).sub.a (OC.sub.2 H.sub.4).sub.b OH,
wherein R is either hydrogen or a hydrocarbon chain having from about 2 to 20 carbon atoms, preferably from about 4 to 18, a and b are each from 0 to 35 and a+b is from 5 to 35. This patent discloses that the fatty acid portion of the soap gel-forming agents should be pure unsaturated or saturated higher fatty acids having a C.sub.14 to C.sub.18 backbone; and that suitable mixtures of such acids can be employed provided that such mixtures are free from significant proportions of other fatty acids of higher or lower chain length which substantially adversely affect or neutralize the desired gel-forming effects.
This patent discloses that examples of fatty acids useful in synthesizing the gel-forming agents include myristic, palmitic, stearic, oleic, linoleic, linolenic, margaric and mixtures of such acids; and that naturally occurring sources of such fatty acids include coconut oil, beef tallow, lanolin, fish oil, bees wax, palm oil, peanut oil, olive oil, cotton seed oil, soy bean oil, corn oil, rapeseed oil, rosin acids and greases.
Similarly, U.S. Pat. No. 4,759,924 to Luebbe, et al teaches a cosmetic composition in the form of solid sticks, having clarity and including from about 40% to about 70% of a polyhydric aliphatic alcohol, from about 3% to about 10% of a soap, from about 1% to about 20% of a hydro-alcoholic soluble emollient, and water. The hydro-alcoholic soluble emollient has the following formula: EQU R(OC.sub.3 H.sub.6).sub.a (OC.sub.2 H.sub.4).sub.b OH,
wherein R is either hydrogen or a hydrocarbon chain having from about 1 to 18 carbon atoms, and a/(a+b).ltoreq.0.5. This patent discloses that the soaps are preferably sodium, potassium and aluminum salts (i.e., soaps) of fatty acids containing from about 14 to 18 carbon atoms.
Each of the following U.S. patents also disclose soap-gelled cosmetic stick compositions:
(1) U.S. Pat. No. 4,944,937 to McCall; PA1 (2) U.S. Pat. No. 4,617,185 to DiPietro; PA1 (3) U.S. Pat. No. 4,702,916 to Geria; PA1 (4) U.S. Pat. No. 5,114,717 to Kuznitz, et al; and PA1 (5) U.S. Pat. No. 5,128,123 to Brewster, et al. The soap gelling agent in each of these patents is described as including, inter alia, sodium salts of higher fatty acids, that is, acids having from 12 to 22 carbon atoms. It is further disclosed in each of U.S. Pat. No. 4,617,185; U.S. Pat. No. 5,114,717; and U.S. Pat. No. 5,128,123 that preferably C.sub.14 -C.sub.18, or C.sub.16 -C.sub.18, fatty acids are utilized as the fatty acid component of the soap gelling agents. None of these five U.S. patents are concerned with providing a gel stick that is stable and maintains its form and aesthetic qualities under hot climatic conditions. Moreover, none of these five U.S. patents even discloses any problems arising in connection with cosmetic or deodorant soap-gelled solid stick compositions maintained under hot conditions.